use strict;
use CGI::Ex::Template;
my $t = CGI::Ex::Template->new;

### hmm - semi documented
$t->_vars({
  PI => 3.14159,
  r  => 1.5,
});

foreach ("2 + 3",
         "1 + (2 + 4) / 3",
         "2 ** 3 ** 4",
         '12345.fmt("%.3e")',
         '0xFF',
         "PI",
         "PI * r ** 2",
         "1 + (",
         "foo",
         "(foo = 123456 + 1)",
         "foo",
         ) {
    my $expr = $_;
    print "-------------\n";
    print "Expression: $expr\n";
    my $optree = eval { $t->parse_expr(\$expr) };
    #use CGI::Ex::Dump qw(debug);
    #debug $optree;

    my $result;
    if (my $err = $@) {
        print "Error:      ".(ref $err ? $err->info : "$err")."\n";
    } else {
        $result = $t->play_expr($optree);
        print "Result:     $result\n";
    }

}